Hi,
What I don't like in your approach is that you require that there is a type (my_table above) for each different rowset traversal "profile" -
I don't. This is not required, this is merely an example. For small tables and simple queries its the fastest way. But not the only way.
interested in only some of the columns - from 2 to 5, typically. Do you require that the application always retrieves all columns?
Absolutely not. odbc::statement s("SELECT column1,column2,etc... FROM ..."); is supported of course.
Just imagine a single table with 4 columns - there are 15 different subsets of columns there (not counting the queries with no columns).
Also there does not have to be a 1:1 relationship between the members in my_table and the columns of the table. Subsets are fine. In fact, if you have a table with 150 columns and want to select only a subset of columns, you have a couple of options with my approach. a) write a struct ... containing only a few member variables for those columns you want to select. b) use individual variables to bind them. c) all of the above Another example: odbc::statement s("SELECT one([bindto]a), two([bindto b), sixteen, seventeen, eighteen FROM huge_table"); long a, b; struct some_struct; // has members m_sixteen, ... some_struct data; s.bind(a, "a"); // bind variable a to column one s.bind(b, "b"); // bind variable b to column b // bind all member variables of 'data' to columns // of the same name ... if they exist s.bind(data);
You does your approach scale in this aspect?
It does.
In my humble opinion, a DB library needs to be usable also with the assumption that each query in a program can potentially retrieve a *different* set of attributes (columns).
Absolutely.
Interesting approach. I'll probably steal ideas from it. Thanks for your comments Hajo -- -------------------------------------------- Lit Window Library - Speed up GUI coding 10x http://www.litwindow.com/library?src=ml wxVisualSetup - integrate wxWidgets into Visual Studio .NET http://www.litwindow.com/Products/products.html?src=ml BugLister - Defect Tracker http://www.litwindow.com/buglister?src=ml Tips & Tricks for wxWidgets & MS Visual Studio http://www.litwindow.com/Knowhow/knowhow.html?src=ml